Buy a 60 amp relay for each headlight beam, and the corresponding connector. A 30 would probably be adequate, but I believe in overkill. The power-carrying wire on the connector will be right for the capacity of the relay. Run a HEAVY wire like a #10 to the area of the radiator core support, then use wires equal to or slightly heavier than the wiring of the relay output to power the headlights. Use one relay for both high beams and another for low, and energize the relays with the dimmer switch output. Have fun!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!